When a telephone is often used to dial the same numbers, it is tedious to manually dial the complete telephone number every time a call is made. Various apparatus have been described which dial such numbers automatically, upon pressing a button, or upon inserting a card into a slot. These apparatus are known as repertory diallers.
Other benefits of repertory diallers include a reduction in the mental and physical effort involved in memorising or finding the telephone number of the called party in a directory, elimination of wrong numbers reached by manual misdialling, and increased ease of telephone use by young, old, and infirm persons, who may find it difficult or impossible to dial intthe customary way.
Known repertory diallers include apparatus in which a telephone number is selected and dialled by pressing one of a plurality of buttons, or by moving a control to one of a plurality of positions, and pressing a single button. Such repertory diallers have a fixed capacity of telephone numbers which can be stored.
Other known repertory diallers use coded cards which are inserted into an apparatus to initiate dialling of the telephone number coded on the card. Such devices are called card repertory diallers. Such diallers are not limited in capacity. Known means for coding such cards include the removal of perforated regions, and insertion of pieces of wire into the cards.